1. Field of the Invention
The present invention relates to a fixing device for mounting a sheet member such as a carpet, an insulator, or the like, on a base such as an automobile floor panel or the like.
2. Description of the Prior Art
As shown in FIG. 3, the passenger compartment in an ordinary automobile has a sheet member 1 such as an insulator and/or a carpet laid on its floor panel for noiseproofing and ornamental purposes and the same is retained by clips 2 so that the sheet member 1 does not turn up.
As is clear from FIG. 4 which is a cross sectional view taken along line 4--4 in FIG. 3, the sheet member 1 comprises an insulator 4 laid on the floor panel 3 and a carpet 5 laid on the insulator 4. The insulator 4 has a laminated structure consisting of a rubber layer 4a and a felt layer 4b. The insulator 4 and carpet 5 have respective through holes 6 and 7. The floor panel 3 has a stud 8 formed upright thereon at each position corresponding to a pair of through holes 6 and 7 of the insulator 4 and carpet 5. After the sheet member 1 has been set in position by inserting the studs 8 into the through holes 6 and 7, the clips 2 are engaged with the studs 8 so as to fix the sheet member 1.
The clip 2 comprises a body portion 12a having a central engaging hole 11 and a head portion 12b integral with one end of the body portion 12a. The inner wall of the body portion 12a defining the central engaging hole 11 is provided with a pair of engaging claws 10 for engaging the thread grooves of the stud 8 so as to non-returnably retain the clip 2.
With this arrangement, the sheet member 1 is mounted on the floor panel 3 by laying the insulator 4 and carpet 5 on the floor panel 3, with their through holes 6 and 7 registered and receiving the studs 8 therein, and pushing the clips 2 against the studs 8 utilizing the through holes 6 and 7, thereby inserting the studs 8 into the central engaging holes 11 of the body portions 12a of the clips 2. At this time, while the head portion 12b of each clip 2 urges the sheet member 1 downward, the engaging claws 10 in the central engaging hole 11 engage with the thread grooves of the stud 8 so that the clip is non-removably retained. Therefore, the sheet member 1 is pinched between the head portion 12b of the clip 2 and the floor panel 3.
According to the prior art fixing device described above, however, there is a possibility of the thread grooves formed in the periphery of the stud 8 colliding against and catching the periphery walls of the through holes 6 and 7 of the insulator 4 and carpet 5, thereby failing to smoothly insert the stud 8 into the through holes 6 and 7 and turning up peripheral wall portions of the insulator 4 and carpet 5 defining the through holes 6 and 7. Thus, the prior art fixing device exhibits inferior operability. In addition, the clip 2 is separate from both the stud 8 and the sheet member 1. For this reason, the clip 2 is troublesome to handle and is easy to misplace or lose.